In order to solve the problems of waste heat utilization

carbon capture and liquid natural gas(LNG)cold energy utilization of solid oxide batteries fueled by methane

a new type of combined cooling

heating and power system was established. The system includes the improved recompression supercritical mixed working fluid Brayton cycle

the transcritical CO_2 heat recovery Rankine cycle and the secondary mixed working fluid organic Rankine cycle. The thermodynamic analysis

equipment exergy analysis

economic cost analysis of the circulation system

and the multi-objective optimization of the system by using the genetic algorithm in MATLAB. The results show that

increasing P1

T16 and the mass fraction of R14 in the second-stage Rankine cycle can improve the network

thermal efficiency

and exergy efficiency of the system

and reduce the average unit cost. P1 is the pressure at inlet the expander in the compressed supercritical mixed working fluid Brayton cycle

T16 is the inlet temperature of the expander in the transcritical CO_2 regenerative Rankine cycle. Under the optimal working conditions

the thermal efficiency

exergy efficiency and average unit cost of the system are 64.70%

47.85% and 24.20 dollars/GJ.